The present invention relates to an auger type icemaker and, more particularly, to an improvement of the extrusion head thereof.
An auger type icemaker is well known in which a water inlet is connected to a refrigeration cylinder having an evaporator of the refrigeration system disposed therearound, a rotatable auger is disposed in the interior of the cylinder and an extrusion head is attached to the upper end thereof. In this icemaker, slush ice formed on the inner wall surface of the refrigeration cylinder is scraped off by said rotatable auger and is guided upward in succession. In the extrusion head, a plurality of bosses are formed to extend axially downward and radially outward, and ice compressing passages are formed between adjacent bosses. Accordingly, said slush ice is compressed together through ice compressing passages and is directed out through discharge ports. However, in such an icemaker, the radial cross sections of the compressing passages disposed in the extrusion head are formed to become small as they approach the discharge ports so as to obtain, by increasing the ice compression ratio, a good quality of less watery ice chunks ordinarily called chip ice.
Therefore, a great pushing force is needed when slush ice is carried into the ice compressing passages and passes through them. However, when the quantity of the carried ice is slightly more than that of the compressed ice, such as in winter, an additional pushing force is needed for passing the ice through the compressing passages of the extrusion head, and ice particles are apt to rotate with the rotatable auger in the circumferential direction, leading to stoppage of the rising ice particles, i.e., choking of the ice.
To remove the above disadvantages, the auger type icemaker shown in FIGS. 1 to 3 has been heretofore presented. In this icemaker, a single rib or a plurality of ribs 22 extending downward at a predetermined length and spacing are embedded in the inner wall surface of the refrigeration cylinder 10 just below the extrusion head 18 attached inside the upper end of the cylinder 10 by means of, for example, set screws. The diameter of the part of spiral edge of the rotatable auger 20 corresponding to said ribs is formed to be slightly smaller than the diameter remaining lower portion of the spiral edge of the auger, so as to rotate free contact with ribs 22. Thus, the rotation of ice particles with the rotatable auger 20 is prevented by ribs 22, and the ice particles are forced to move upward thereby to obtain a much greater pushing force than the one needed when they pass through ice compression passages 16 of the extrusion head 18, leading to prevention of the condition where ice cannot pass through passages 16 of the extrusion head 18, i.e., the occurrence of choking. The above conventional auger type icemaker has a very excellent advantage in that the occurrence of ice choking is effectively prevented. However, since the ribs 22 embedded in the inner surface of the refrigeration cylinder 10 are constituent elements for obtaining the above advantages, there exist the following problems in the manufacture of the cylinder.
(1) Notches 23 must be formed so as to embed ribs in the refrigerated cylinder, and a troublesome cutting operation is needed to form the notches since they are not through grooves.
(2) The ribs must have a magnitude large enough to prevent rotation of ice particles, so that a difficult welding-in operation is needed in the interior of the refrigeration cylinder after the ribs are embedded therein. Furthermore, there is the possibility of ribs falling out due to poor welding or fatigue of the welding portions.
(3) There are cases where distortion occurs in the refrigeration cylinder due to the rib welding.
The object of the present invention is to provide an improved auger type icemaker which removes the above problems of the conventional auger type icemaker without inducing choking of the ice particles.